General Properties of Waves

Question 1

when are any 2 points of a wave in phase?

Answer 1

1) moving in same direction
2) moving at same speed and at same displacement from rest position

Question 2

what happens when water waves are refracted in shallower water?

Answer 2

wavelength decreases, speed decreases, direction of wave bends towards normal

Question 3

what are 3 similarities between transverse and longitudinal waves?

Answer 3

1) both transfer energy from one point to another without transfer of matter
2) both undergo reflection and refraction
3) both obey the general wave equation

Question 4

what are 2 differences between transverse and longitudinal waves?

Answer 4

1) transverse - crest and trough; longitudinal - compression and rarefaction
2) transverse - direction of vibration of particles perpendicular to direction of wave propagation; longitudinal - direction of vibration of particles parallel to direction of wave propagation

Question 5

what is the speed of sound and light?

Answer 5

sound: ~330 m/s
light: ~3.0 x 10⁸ m/s

Question 6

why is the speed of sound different in solids liquids and gases?

Answer 6

1) difference in strength of forces between particles
2) closeness of particles
3) temperature

Question 7

what are the 3 uses of ultrasound?

Answer 7

1) ultrasound echolocation
- time taken for sound pulse to travel down and up used to determine depth of underwater objects

2) medical scanning of soft tissue
- pre-natal scanning used to check on growth of an unborn baby
- scanner transmits ultrasound into mother’s body and reflections display as a picture on a screen

3) quality control of manufacturing processes
- used to check for cracks in concrete

*to answer how ultrasound is used to study unborn babies, mention definition of ultrasound, series of compressions and rarefactions throughout body tissue, body tissue particles vibrate parallel to wave, ultrasound hit a denser region (baby) and reflected back to receiver